https://fex.net/uk/s/dnkyx4s
10 day
Happy New Year to you as well. It took a while to clean up the current state of LTN in order to see how things went down hill. In short, it isn't a combinator issue. This LTN Combinator only gives you a UI for the LTN signals you need to set. If you use a standard Constant Combinator with the same singnals you'll have the same problem.
A primay problem is timing in your sysmtem. It cascades into other issues as more time goes on. Your LTN setting for 'Delivery timeout (sec)' is 1800 (30 Minutes). However, it takes over 17 minutes to load and 17 minutes to unload your train cars with your yellow belts.
Ore stack: 2000
Car slots: 64
Items in car: 128000
Your yellow belt (mini-loader) speed is 20 items / second
Loaders per car: 6
(Un)-load rate: 120 / second
128000 / 120 ~= 1067 seconds (17.79 minutes) time to each load and unload.
You don't even have enough time for a full train to load and unload a delivery before LTN marks it lost and deletes the delivery and dispatches a new train. Add in travel time from depot -> provider, provider -> requester, and requester -> depot, you need even more time. Then add to this stations that you DO allow more than one train. You could have triains waiting up to that multiple of 17.79 minutes before it gets to start unloading.
As this cascades, it results in trains delivering materials to stations that no longer have space for the cargo because the filled up in the waiting time. Then trains show back up at the depot with resdiuals, if they're not all cleaned up residuals then get deposited to the wrong station... it gets messy.
Hope this helps.